BMI Calculator
Enter your height and weight to calculate your Body Mass Index (BMI) and find out which category you fall into.
BMI Calculator: Body Mass Index by Height and Weight
BMI — Body Mass Index — is the most widely used metric for tracking weight relative to height. What you see in the mirror may not give you the full picture; a number provides an objective starting point. To find out whether your weight is in a healthy range for your height, you only need two values: height and weight.
What Is BMI and Why Does It Matter?
BMI is calculated by dividing your weight in kilograms by the square of your height in metres. The World Health Organization divides the result into four categories: below 18.5 is underweight, 18.5–24.9 is normal, 25–29.9 is overweight, and 30 or above is obese. On its own it does not diagnose anything, but it works as a quick filter for assessing long-term health risks.
For example, a person 1.75 m tall and weighing 90 kg has a BMI of 29.4 — placing them in the overweight category. The same height at 70 kg gives 22.9, which falls in the normal range. The difference may seem small, but over time it significantly shifts the long-term metabolic risk profile.
How to Use the BMI Calculator
Required Inputs
- Height (cm) — Morning measurement is recommended; it can vary by 1–2 cm during the day.
- Weight (kg) — Measure before breakfast, under consistent conditions.
Formula and Logic
The formula is: BMI = Weight (kg) ÷ [Height (m) × Height (m)]. Height is first converted to metres (cm ÷ 100), squared, then divided into weight. The calculator handles this automatically — you only need to enter the raw values.
The tool also shows the weight range considered normal for your height — the minimum and maximum weight corresponding to a BMI of 18.5–24.9.
Example Scenarios
| Height | Weight | BMI | Category |
|---|---|---|---|
| 160 cm | 50 kg | 19.5 | Normal |
| 175 cm | 70 kg | 22.9 | Normal |
| 180 cm | 90 kg | 27.8 | Overweight |
| 175 cm | 110 kg | 35.9 | Obese |
This tool is for informational purposes only. Consult a doctor or dietitian for health decisions.
How to Interpret Your Results
The result shows both your numerical value and your category. Falling in the normal range is a positive sign, but additional indicators — waist circumference, fat distribution, and blood markers — should not be ignored. If you fall in the overweight or obese range, this is not a diagnosis but a warning signal.
For muscular or athletic individuals, BMI can be misleading. Muscle tissue is heavier than fat tissue, which can push the value artificially high. For this reason, interpreting the result alongside your lifestyle and overall health picture provides a more accurate assessment.
Tips for Accurate Results
- Measure your height in the morning, barefoot, standing straight.
- Always weigh yourself at the same time of day — preferably in the morning before eating.
- Do not make decisions based on a single measurement; take an average over several days.
- During pregnancy or with significant oedema, weight readings can be misleading — consult a health professional in these cases.